Name: Does a Coffee a Day Keep AF at Bay?
Creator: Prof. Peter Barlis
Published: 2026-04-22T13:02:27+10:00

Does a Coffee a Day Keep AF at Bay?

The landmark DECAF trial, published in JAMA, found that moderate coffee drinking may actually protect against AF recurrence — overturning decades of routine clinical advice.

Prof. Peter Barlis

April 22, 2026

Key Points

A new clinical trial published in JAMA found that patients with atrial fibrillation who continued drinking around one cup of coffee a day were 39% less likely to have a recurrence of AF compared to those who stopped completely.
This is the first randomised clinical trial to directly test whether coffee triggers AF episodes, overturning decades of routine clinical advice to avoid caffeine.
The finding does not mean patients should increase their coffee intake, and it does not apply to everyone. The trial involved patients who were already moderate coffee drinkers.
As with all research, there are limitations, and guidelines have not yet changed. Talk to your cardiologist before changing anything about your daily habits.

If you have been told you have atrial fibrillation, there is a good chance someone, whether a doctor, a nurse, or a well-meaning friend, has suggested you cut back on coffee. For years, caffeine has been viewed with suspicion in the context of heart rhythm disorders, and many patients with AF have quietly given up their morning cup out of caution. If you experience palpitations or an irregular heartbeat and are not sure whether it is related to AF, our dedicated article on palpitations explains what different sensations mean and when to seek help.

A major new clinical trial, published in JAMA in 2026 and conducted across five hospitals in Australia, the United States, and Canada, has now challenged that longstanding advice in a way that will be meaningful for many people living with AF.

The short version: in patients who already drank moderate amounts of coffee, continuing to drink around one cup a day after cardioversion was not harmful, and may actually have been protective against the return of irregular heart rhythm.

What is the DECAF trial?

DECAF stands for Does Eliminating Coffee Avoid Fibrillation, which neatly captures the question the researchers set out to answer. It is the first randomised clinical trial ever conducted on this specific question, which makes it a landmark study even by the standards of cardiology research.

The trial enrolled 200 adults with persistent AF who were all scheduled for cardioversion, the procedure that uses a controlled electrical impulse to reset the heart back into a normal rhythm. The average age of participants was 69 years and 71% were male. All were moderate coffee drinkers, consuming around seven cups per week, which is roughly one cup a day, at some point in the previous five years.

After successful cardioversion, patients were randomly assigned to one of two groups. One group was asked to continue drinking at least one cup of caffeinated coffee each day. The other group was asked to avoid all coffee and caffeine entirely, including decaffeinated coffee. Most participants were already being treated for AF with anticoagulation and some with antiarrhythmic or rate control medications, and these were continued throughout the trial. Both groups were then followed for six months to see whose heart rhythm stayed normal and whose returned to AF. The coffee group maintained their habit of around seven cups per week throughout the trial, while the abstinence group reduced to essentially none.

☕ Coffee group

47% of patients who continued drinking coffee had a recurrence of AF or atrial flutter within six months.

🚫 No coffee group

64% of patients who avoided all caffeine had a recurrence of AF or atrial flutter within six months.

📉 The difference

Patients who continued drinking coffee were 39% less likely to have a recurrence of AF compared to those who abstained entirely.

✅ Safety

Emergency visits and hospitalisations were similar between both groups. No deaths occurred in either group during the trial.

☕ What does this mean in practice?

For every 6 people with AF who continued drinking their daily coffee after cardioversion, approximately 1 avoided a recurrence that they would otherwise have had. That is a meaningful real-world benefit, and a number worth discussing with your cardiologist.

The result was statistically significant, meaning it is unlikely to be explained by chance alone. The lead investigator, Professor Christopher Wong of the University of Adelaide, described the results as astounding, noting that the trial suggests coffee is not only safe but potentially protective for patients with AF. Importantly, the DECAF trial was funded by the National Institutes of Health, with no pharmaceutical or industry sponsorship involved, which strengthens confidence in the independence of the findings.

Why might coffee help rather than hurt?

For decades, the assumption was that caffeine, as a stimulant, would make the heart more prone to irregular rhythms. The DECAF trial suggests the reality is more nuanced. The researchers and commentators offered several possible explanations for why moderate coffee consumption might actually be associated with fewer AF episodes.

Adenosine blockade

Caffeine blocks adenosine receptors in the heart. Adenosine can promote the conditions that allow AF to develop and persist, so blocking it may have a protective effect.

Anti-inflammatory effects

Coffee contains compounds beyond caffeine that have anti-inflammatory properties. Inflammation plays a role in the development of AF, so reducing it may help maintain normal rhythm.

Physical activity

Coffee is associated with increased physical activity, and exercise is known to reduce AF burden. Patients in the coffee group may have been more active as a result.

Caffeine withdrawal

Abruptly stopping caffeine causes physiological changes that may themselves be disruptive to heart rhythm. Regular moderate consumption avoids this stress on the body.

What are the limitations of this trial?

No single clinical trial, however well-designed, changes medical practice on its own, and the DECAF researchers themselves were careful to highlight several important limitations that patients should understand.

The trial enrolled 200 patients, which is a relatively modest number in the world of clinical cardiology. While the result was statistically significant, a larger study could either strengthen or modify these findings. The open-label design, meaning that both patients and researchers knew which group each person was in, could also influence how symptoms were reported or how often patients sought medical attention. There were also some differences in baseline characteristics between the two groups: the abstinence group was on average two years older and included more women, which may have influenced the results despite statistical adjustments.

The researchers also noted that AF episodes were detected through routine clinical care rather than a standardised monitoring schedule, which means some episodes in either group may not have been captured.

For years I have had the conversation in clinic about coffee and AF. Most patients ask about it, and until now the honest answer was that we did not have good randomised evidence either way. The DECAF trial changes that. For patients who are already moderate coffee drinkers, this is genuinely reassuring. But it is not a signal to start drinking more, and it is not a study of patients who never drank coffee. Context matters, and the conversation with your cardiologist still matters.

What does this mean for you?

If you have AF and you have been worried about your morning coffee, this trial offers genuine reassurance. For patients who are already moderate coffee drinkers, the best available evidence now suggests that continuing to drink around one cup a day is not harmful and may, if anything, be beneficial for heart rhythm stability after cardioversion.

However, it is important to understand what this trial does not tell us. It was not conducted in people who do not drink coffee at all, so it does not suggest that non-coffee-drinkers should start. It does not apply to large amounts of caffeine. It does not mean that every patient with AF should drink more coffee. And it does not override the advice of your own cardiologist, who knows your specific heart anatomy, medications, and circumstances.

Clinical guidelines have not yet been updated to reflect this trial, and further research will follow. In the meantime, the most sensible message is that you no longer need to feel guilty about your morning cup, but as always, any significant changes to your lifestyle or habits are worth discussing with your clinical team first.

Conclusion

The DECAF trial is a genuinely important piece of research that challenges a longstanding assumption in cardiology. For decades, patients with AF have been advised, often without strong evidence, to avoid caffeine. The first properly conducted randomised trial on this question tells a different story: for moderate coffee drinkers, continuing to enjoy one cup a day after cardioversion appears to be safe and may reduce the likelihood of AF returning.

It is a finding worth knowing about. It is also a reminder that in medicine, advice that has been repeated for many years is not always grounded in the evidence we now have the tools to generate. This trial gave us that evidence, and it is genuinely good news for the many patients with AF who have been quietly missing their coffee.

References

Wong CX, Cheung CC, Montenegro G, et al. Caffeinated Coffee Consumption or Abstinence to Reduce Atrial Fibrillation: The DECAF Randomized Clinical Trial. JAMA. 2026;335(4):317-325. doi:10.1001/jama.2025.21056
First presented by Christopher X. Wong, MBBS, MPH, PhD, at the American Heart Association Scientific Sessions 2025, New Orleans, LA, November 9, 2025. Published in print JAMA January 27, 2026
Funding: The DECAF trial was supported by the National Institutes of Health (NIH), National Heart, Lung and Blood Institute. No commercial or industry funding was involved in this research.